When you modify a brush in 'Geometry Editing panel, the pivot of the brush is decentralized. This is very bad for a future edition.
If anyone out there using/used the CryEngine, know that when the pivot is decentralized, there is a button called ‘Reset Xform’, which centered pivot with the Solid, this is very useful I think.
It would be interesting to have this option in Unreal 4.
Thank you for your attention.